/**
 * Created by su on 2017/8/24.
 */
//判断大鱼和果实的距离
function  momFruitsCollision() {
    for(var i = 0; i < fruit.num; i++) {
        if(fruit.alive[i]){
            var  l = calLength2(fruit.x[i], fruit.y[i], mom.x,mom.y);
            if(l < 900) {
                fruit.dead(i);
            }
        }
    }
}